Physical activity, weekend catch-up sleep, and depressive symptoms: mediating effects of high-sensitivity C-reactive protein

Background: We aimed to examine the effect of physical activity (PA) and weekend catch-up sleep (WCS) on depressive symptoms by evaluating their effects on high-sensitivity C-reactive protein (hsCRP) levels. Methods: Data were collected from 10,715 adults aged ≥19 years. PA and depressive symptoms were assessed using self-report scales. The WCS was calculated by subtracting self-reported average weekday sleep hours from weekend sleep hours, and serum hsCRP levels were measured using immunoturbidimetric methods. Given that depressive symptoms are characterized by their multifaceted nature, we identified specific symptoms associated with hsCRP levels. Path analysis was used to investigate the association between PA, WCS, hsCRP, and depressive symptoms, and that between PA, WCS, hsCRP, and specific symptoms related to hsCRP. Results: Higher levels of PA and WCS were associated with a decreased risk of depressive symptoms through lowering hsCRP levels. Among various depressive symptoms, sleep problems and appetite changes were associated with hsCRP. In pathway analyses using them as dependent variables, higher levels of PA and WCS were also associated with a decreased risk of sleep problems and appetite changes through lowering hsCRP levels. Limitations: The current study employed a cross-sectional design, and WCS and PA were based on participants' self-reports rather than objective measurements. Conclusions: Increased levels of PA and WCS may help alleviate depressive symptoms, particularly sleep problems and appetite changes, by mitigating chronic inflammation. Therefore, ensuring adequate exercise time and compensating for inadequate weekday sleep during weekends are crucial for maintaining mental well-being.